What is selenium? Selenium is a trace mineral that is essential to good health but required only in small amounts. Selenium is incorporated into proteins to make selenoproteins, which are important antioxidant enzymes. The antioxidant properties of selenoproteins help prevent cellular damage from free radicals.
Free radicals are natural by-products of oxygen metabolism that may contribute to the development of chronic diseases such as cancer and heart disease. Other selenoproteins help regulate thyroid function and play a role in the immune system.
What foods provide selenium? Plant foods are the major dietary sources of selenium in most countries throughout the world. The content of selenium in food depends on the selenium content of the soil where plants are grown or animals are raised. For example, researchers know that soils in the high plains of northern Nebraska and the Dakotas have very high levels of selenium. People living in those regions generally have the highest selenium intakes in the United States (U.S.).
In the U.S., food distribution patterns across the country help prevent people living in low-selenium geographic areas from having low dietary selenium intakes. Soils in some parts of China and Russia have very low amounts of selenium. Selenium deficiency is often reported in those regions because most food in those areas is grown and eaten locally. Selenium also can be found in some meats and seafood.
Animals that eat grains or plants that were grown in selenium-rich soil have higher levels of selenium in their muscle. In the U.S., meats and bread are common sources of dietary selenium. Some nuts are also sources of selenium. Selenium content of foods can vary. For example, Brazil nuts may contain as much as 544 micrograms of selenium per ounce. They also may contain far less selenium. It is wise to eat Brazil nuts only occasionally because of their unusually high intake of selenium. Selected food sources of selenium are provided in Table 1.
Table 1: Selected food sources of selenium
Food | Micrograms (μg) | Percent DV* |
Brazil nuts, dried, unblanched, 1 ounce | 544 | 780 |
Tuna, light, canned in oil, drained, 3 ounces | 63 | 95 |
Beef, cooked, 3½ ounces | 35 | 50 |
Spaghetti w/ meat sauce, frozen entrée, 1 serving | 34 | 50 |
Turkey, light meat, roasted, 3½ ounces | 32 | 45 |
Beef chuck roast, lean only, roasted, 3 ounces | 23 | 35 |
Chicken Breast, meat only, roasted, 3½ ounces | 20 | 30 |
Noodles, enriched, boiled, 1/2 cup | 17 | 25 |
Macaroni, elbow, enriched, boiled, 1/2 cup | 15 | 20 |
Egg, whole, 1 medium | 14 | 20 |
Cottage cheese, low fat 2%, 1/2 cup | 12 | 15 |
Oatmeal, instant, fortified, cooked, 1 cup | 12 | 15 |
Rice, white, enriched, long grain, cooked, 1/2 cup | 12 | 15 |
Rice, brown, long-grained, cooked, 1/2 cup | 10 | 15 |
Bread, enriched, whole wheat, commercially prepared, 1 slice | 10 | 15 |
Walnuts, black, dried, 1 ounce | 5 | 8 |
Bread, enriched, white, commercially prepared, 1 slice | 4 | 6 |
Cheddar cheese, 1 ounce | 4 | 6 |
*DV = Daily Value.
DVs are reference numbers developed by the Food and Drug Administration (FDA) to help consumers determine if a food contains a lot or a little of a specific nutrient.
The DV for selenium is 70 micrograms (ug). Most food labels do not list a food's selenium content. The percent DV (%DV) listed on the table indicates the percentage of the DV provided in one serving.
A food providing 5% of the DV or less is a low source while a food that provides 10-19% of the DV is a good source. A food that provides 20% or more of the DV is high in that nutrient. It is important to remember that foods that provide lower percentages of the DV also contribute to a healthful diet. For foods not listed in this table, please refer to the U.S. Department of Agriculture's Nutrient Database.
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